Continuation of molecular biological, immunological and epitope analysis of toxic shock syndrome toxin 1 is proposed. The unique genetic element associated with tst, the TSST-1 gene, will be mapped and sequenced and tested for transposability. A recently discovered association between tst, trp, and an integrated bla determinant will be characterized at the molecular level. Epitopes involved in mutagenicity and in immune protection will be charcterized and mapped on the TSST-1 molecule and specific and non-specific TSST-1 receptors will be identified and their role in the cytopathology of TSS will be investigated. Finally, tst null mutants of TSS strains isolated from chronic carriers will be used in displacement therapy to eliminate the carrier state.